Batteries are widely used to provide power, or back-up power, to electronic devices, and especially portable electronic devices including mobile communication devices. While the lifetime of such batteries has improved over the last several years, the demand for battery power has increased as the use of the electronic devices increase due to consumer habits. Extended use of the electronic device may result in a “dead” battery and great frustration to the consumer.
Most consumers find it helpful to have an indication on the electronic device of battery power remaining for use (commonly called residual power). This indication is typically represented by a number or bar graph on a display of the electronic device as a percentage of a fully charged battery.
There are several known methods of determining battery levels. One method determines battery residual charge and battery capacity (total battery capability) by applying discharging pulses and rest periods to a battery, measuring the voltage drop as an index to determine the potential maximum battery capacity. The known art typically uses an open battery voltage to determine the present capacity (residual battery charge).
However, these known methods of estimating the residual battery charge by battery voltage are typically somewhat inaccurate. One disadvantage of these known methods is that the voltage of the battery depends on the current that is drained by the load, with the voltage changing after the load is decreased. For example, the remaining voltage indication increases when a cell phone call is released after use.
Accordingly, it is desirable to provide a method for determining the residual charge on a battery without relying only on battery voltage. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.